Former Stanford tennis player Bradley Klahn ’12 pulled one of the upsets of the U.S. Open so far on Wednesday.

The 2010 NCAA singles champ knocked off the No. 36 player in the world, Austria’s Jurgen Melzer, in five sets, 4-6, 6-3, 7-5, 5-7, 6-4. If he can also defeat No. 13 Frenchman Richard Gasquet, he may set up a rematch of the 2011 NCAA singles final with USC’s Steve Johnson, who stunted Klahn’s defense of the title and went on to win two crowns in a row himself. Klahn will also compete in the doubles tomorrow with fellow American Chase Buchanan at 11 a.m. EST.

On the women’s side, senior Mallory Burdette continued her impressive run with a 6-2, 6-4 win over the Czech Republic’s Lucie Hradecka, setting up a third-round match with No. 3 Maria Sharapova.

Burdette’s Cardinal doubles partner, junior Nicole Gibbs, dropped out of the competition Wednesday after losing her first-round match to France’s Alize Cornet. Burdette and Gibbs were set to face the Williams sisters on Wednesday.

—Joseph Beyda